1. Field of the Invention
The present invention relates to a shuttle for a feedbox of a block machine, wherein the shuttle has a shuttle slide with a shuttle rodding and the shuttle slide is connected to a drive.
2. Description of the Related Art
Block machines are known in the prior art in manifold embodiments. Substantially, in a synchronized process a stone mould should be provided, a concrete mixture should be filled into the moulding cavities of the stone mould, the concrete mixture should be packed with a tamper and/or a vibrator, and subsequently the thus produced final concrete products, the so-called moulded articles, should be demoulded. Here, it has been proven successful to feed the block machines with bolster pallets and to lower upwards and downwards open stone moulds onto the bolster pallets. The concrete mixture is filled from concrete hoppers into one or more feedboxes and let from the feedboxes into the stone mould. Subsequently, the bolster pallet is vibrated with a vibration unit and/or a tamper is lowered into the stone mould. In this way, the concrete is packed in the stone mould. In the next step the tamper and the mould are lifted again and the bolster pallet with the moulded articles is taken out of the block machine.
Here, the quality and strength of the moulded articles strongly depend on the filling of the stone mould by the feedbox. Since the filling level related material pressure in the feedbox decreases during the travel of the feedbox and during the progressive filling of the stone mould, respectively, the rear moulding cavities in the filling direction are filled less. Thus, there is obtained an unintentional and declining filling curve over the width of the stone mould to be filled. This problem in particular arises when tall or slim stone moulds, respectively, are filled. The varying mass distribution over the stone mould as well as the resulting mass difference have a negative effect on the stone density and optics and may also have an interfering effect on the subsequent processes.
In order to minimize these problems as far as possible the employment of so-called shuttles has been proven successful. For that, a shuttle slide with a rodding substantially moves horizontally back and forth within the feedbox during the filling operation. This causes, that the raw material can be uniformly distributed into the stone mould. The movement of the shuttle slide takes place via a drive that is connected to the shuttle slide.
However, the shuttles known from the prior art have the drawback that the horizontal lifting component of the shuttle that can vary according to the width or length of the product, respectively, can only be adjusted at great expense or even not at all. Further, also the force necessary for the movement of the raw material is given by the physical properties of the raw material. Thus, a denser concrete requires a higher effort for movement. Also this can only partly be adjusted with the known shuttles or not at all. In the end, also with the shuttles known from the prior art there is an increased wear of the guides of the shuttle slide on the feedbox.